My new SE came with a T-Mobile SIM already in it.
As it was, I was not able to get through the setup screens without activating the SIM (calling T-Mobile).
To get through the setup without activating the SIM, I had to,
1) Removed the SIM. Midway down the right hand side, is a small hole used to release the SIM. After
completely powering down, I carefully used a small bent paper clip to eject the SIM and then removed it from the SE.
2) Powered the SE back up and connected it to my computer using the USB to lightning cable that comes with the SE.
3) Opened iTunes and verified that the SE showed up in the left hand column.
4) With my SE still connected to my computer, ran through setup on my SE.
5) After it was setup, I disconnected the SE from my computer, completely powered the SE down, and inserted the SIM card I bought from
Mint Mobile.
I wanted to load the iTunes backup from my iPod Touch 6 into the SE but the SE was iOS 10.2 and my Touch 6 was iOS 10.3 . I ended up having to update the SE to the latest iOS (I was going to anyways) before I could restore the Touch 6 iTunes backup into the SE (with the SE connected to my computer and my computer running iTunes). After disconnecting from iTunes, I went into settings > about and changed the iPhone name (restoring the backup from my Touch had renamed my SE to the name my Touch was called). I then connected my SE to my computer and backed up the SE under the new name in iTunes.
As a final step since this was my first iPhone, I had to clean up my contact list on iCloud. I ran the contacts app on my computer and added all the information from my Samsung. I also deleted contact information I no longer needed and updated the information that was already there. This by far was the most time consuming part of getting the SE operational

.